Tone signal generation device having a tone sampling function

Abstract

A tone signal applied from outside is sampled by a tone sampling device and the sampled waveshape data is written into a memory. During this writing operation and in parallel with the writing operation, a zero crossing point of the waveshape in terms of the sample data of the tone signal is detected. A final address detection circuit stores, each time a zero cross has been detected, a write address of the waveshape sample data with respect to the memory. Address data which is stored in the final address detection circuit when the writing of the waveshape sample data in the memory has been completed is detected as a final address of the sampled waveshape data. The waveshape data in the memory is read out either in a forward direction in a reverse direction using this final address as a start point or an end point and a tone signal corresponding to the sampled waveshape data is sounded. Such address constituting the start point or end point of reading, i.e., a reference address, can be adjusted by a reference address adjuster. It is also possible, upon completion of the writing into the memory, to read out waveshape data immediately from the memory thereby to immediately and automatically sound the sampled waveshape data which has just been written into the memory.

What is claimed is: 
     
       1. A tone signal generation device comprising: tone sampling means for sampling a tone signal;   memory means, capable of both reading and writing, for storing waveshape sample data;   write control means for writing waveshape sample data of the tone signal sampled by said tone sampling means into said memory means;   zero cross detection means for detecting, simultaneously with the writing of waveshape sample data of the tone signal sampled by said tone sampling means into said memory means, zero crossings representative of zero crossings of the tone signal;   final address detection means for storing a write address of waveshape sample data in said memory means each time a zero crossing is detected by said zero cross detection means and detecting a final address stored when writing has been completed as a final address of said waveshape sample data;   read control means for reading out said waveshape sample data in said memory means, wherein said read control means is capable of reading out said waveshape sample data in a forward direction and in a reverse direction, said read control means using the final address detected by said final address detection means as an end point or a start point for reading out said waveshape sample data; and   means for generating a tone signal corresponding to said waveshape sample data read out from said memory means.   
     
     
       2. A tone signal generation device as defined in claim 1 wherein said final address detection means stores, in unit of a block consisting of plural addresses, a block corresponding to the address for which zero cross has been detected and detects a final address in a final block stored when writing has been completed as said final address of said waveshape sample data. 
     
     
       3. A tone signal generation device as defined in claim 1 wherein said zero cross detection means detects whether level of said tone signal or said waveshape sample data has entered a predetermined zero judgement range or not. 
     
     
       4. A tone signal generation device as set out in claim 1, wherein said zero cross detection means detects zero crossings of the tone signal. 
     
     
       5. A tone signal generation device as set out in claim 1, wherein said zero cross detection means detects zero crossings of the waveshape sample data. 
     
     
       6. A tone signal generation device comprising: sampling means for sampling a tone signal;   memory means, capable of both reading and writing, for storing waveshape sample data;   write control means for writing waveshape sample data of the tone signal sampled by said tone sampling means into said memory means;   read control means for reading out said waveshape sample data in said memory means, wherein said read control means is capable of reading out said waveshape sample data in a forward direction and in a reverse direction, said read control means using a predetermined reference address as a start point or an end point for reading out said waveshape sample data;   reference address adjusting means for increasing or decreasing the reference address; and   means for generating a tone signal corresponding to said waveshape sample data read out from said memory means.   
     
     
       7. A tone signal generation device as defined in claim 6 wherein said read control means can select whether said waveshape sample data should be repeatedly read out or not and said reference address adjusting means can increase or decrease the reference address when the repeated reading of the waveshape sample data has been selected by said read control means. 
     
     
       8. A tone signal generation device as defined in claim 6 wherein said write control means writes said waveshape sample data from a predetermined head address and said reference address is a final address of said waveshape sample data written in said memory means. 
     
     
       9. A tone signal generation device as defined in claim 6 wherein said reference address is a head address or final address of said waveshape sample data written in said memory means and said reference address adjusting means changes at least one of the head address and the final address. 
     
     
       10. A tone signal generation device as defined in claim 6 wherein said reference address adjusting means increases or decreases the reference address in unit of a block consisting of plural addresses. 
     
     
       11. A tone signal generation device comprising: tone sampling means for sampling a tone signal;   memory means, capable of both reading and writing, for storing waveshape sample data;   write control means for writing waveshape sample data of the tone signal sampled by said tone sampling means into said memory means;   read control means for reading out said waveshape sample data written in said memory means, in response to completion of writing of said waveshape sample data in said memory means, to reproduce the sampled tone signal, and   means for providing a tone signal corresponding to said waveshape sample data read out from said memory means upon said completion of writing.   
     
     
       12. A tone signal generation device as defined in claim 11 wherein said read control means comprises write completion detection means for detecting completion of writing of said waveshape sample data, means for generating a readout start signal in response to the detection of completion of writing and means for reading out said waveshape sample data written in said memory means in response to the readout start signal. 
     
     
       13. A tone signal generation device as defined in claim 12 wherein said write completion detection means detects completion of writing by detecting that the write address in said memory means has reached a final address of a memory area of waveshape sample data for one tone in said memory means. 
     
     
       14. A tone signal generation device as defined in claim 11 wherein said read control means performs reading at the same rate as a rate of writing the waveshape sample data by said write control means. 
     
     
       15. A tone signal generation device as defined in claim 11 further comprising means for controlling tone signal generation by controlling an amplitude with an envelope of a substantially uniform level from start of sounding of the tone to the end of sounding of the tone. 
     
     
       16. A tone signal generation device as defined in claim 11 further comprising sounding control means, for controlling sounding of the tone signal, comprising means for detecting an address at which a final portion of the waveshape sample data is stored in said memory means and means for finishing sounding when read address in said memory means has reached said address at which the final portion of waveshape sample data is stored. 
     
     
       17. A tone signal generation device comprising: tone sampling means for sampling a tone signal;   memory means, capable of both reading and writing, for storing waveshape sample data;   write control means for writing waveshape sample data of the tone signal sampled by said tone sampling means into said memory means;   read control means for reading out waveshape sample data stored in said memory means in a reverse direction and thereafter continuously reading out the same waveshape sample data in a forward direction; and   means for generating a tone signal corresponding to said waveshape sample data read out from said memory means by said read control means.   
     
     
       18. A tone signal generation device as defined in claim 17 wherein said read control means performs control in such a manner that the reading of said waveshape sample data in the reverse direction and the subseqent reading in the forward direction are made repeatedly. 
     
     
       19. A tone signal generation device as defined in claim 17 wherein said read control means comprises U turn reading selection means for selecting reading of the waveshape sample data stored in said memory means in a forward direction and subsequently in the reverse direction and reverse reading selection means for selecting reading of the waveshape sample data stored in said memory means and, when the U turn reading and the reverse reading have been selected simultaneously by said U turn reading selection means and said reverse reading selection means, the read control means performs control in such a manner that the waveshape sample data is read out in the reverse direction and then continuously the waveshape sample data is read out in the forward direction. 
     
     
       20. A tone signal generation device comprising: tone sampling means for sampling a tone signal;   memory means capable of both reading and writing for storing waveshape sample data;   write control means for writing waveshape sample data of the tone signal sampled by said tone sampling means into said memory means;   selecting means for selecting a predetermined performance mode;   read control means for reading out said waveshape sample data stored in said memory means repeatedly when said predetermined performance mode has been selected by said selecting means;   wherein waveshape sample data stored in the memory means is imparted with an envelope covering from a rise portion to a fall portion of a single repeating period; and   envelope imparting means for imparting a gradually attenuating tone volume envelope to a tone signal generated in accordance with waveshape sample data repeatedly read out over plural repeating periods from said memory means by said read means.   
     
     
       21. A tone signal generation device as defined in claim 20 wherein attenuation time of the tone volume envelope imparted by said envelope imparting means is sufficiently longer than one repeating period of said waveshape sample data. 
     
     
       22. A tone signal generation device comprising: tone sampling means for sampling a tone signal and providing waveshape sample data corresponding to the sampled tone signal;   memory means, capable of both reading and writing, for storing waveshape sample data;   write control means for writing the waveshape sample data of the tone signal sampled by said tone sampling means into said memory means;   final address detection means for detecting a final address of the waveshape sample data written in said memory means;   overwrite control means associated with said write control means for adding waveshape sample data which has newly been sampled by said tone sampling means to waveshape sample data stored in said memory means and causing waveshape sample data which is a result of the addition to be written into said memory means;   final address detection control means associated with said final address detection means and said overwrite control means for performing control in such a manner that, when the adding by said overwrite control means is performed, either a final address of waveshape sample data which is already stored in said memory means or a final address of waveshape sample data of a tone signal which has newly been sampled by said tone sampling means having a larger data size is detected as a final address of waveshape sample data which is a result of addition;   read control means for reading out waveshape sample data stored in said memory means, wherein said read control means is capable of reading out said waveshape sample data in a forward direction and in a reverse direction, said read control means using said final address detected by said final address detection means as an end point or a start point; and   means for generating a tone signal corresponding to the waveshape sample data read out from said memory means.   
     
     
       23. A tone signal generation device comprising: tone sampling means for sampling a tone signal and providing waveshape sample data corresponding to the sampled tone signal;   memory means, capable of both reading and writing, for storing waveshape sample data;   write control means for writing the waveshape sample data of the tone signal sampled by said tone sampling means into said memory means;   read control means for reading the waveshape sample data stored in said memory means, and generating a tone signal corresponding to the read out waveshape sample data;   operation means for selecting or setting the reading operation of said read control means and for setting or adjusting data associated with the reading control by said read control means; and   cancel means for restoring data associated with the reading operation selected or set by said operation means to a predetermined initial state.   
     
     
       24. A tone signal generation device comprising: tone sampling mean for sampling a tone signal;   memory means, capable of both reading and writing, for storing waveshape sample data;   write control means for writing waveshape sample data of the tone signal sampled by said tone sampling means into said memory means;   zero crossing detection means for detecting zero crossings representative of zero crossings of the tone signal during writing of the waveshape sample data into said memory means;   final address detection means for storing a write address of waveshape sample data in said memory means each time a zero crossing is detected by said zero crossing detection means and detecting a final address stored when writing has been completed as a final address of said waveshape sample data;   read control means for reading out said waveshape sample data in said memory means; and   mean for generating a tone signal corresponding to said waveshape sample data read out from said memory means.